The present invention relates to a device and method for analyzing bodily fluids of bodily secretions to diagnose a pathological state. More specifically, the present invention relates to a device and method for sampling bodily fluids collected by and contained in an absorbent pad and subsequently relaying the samples to an analyzer which performs a series of analytical tests either simultaneously or in sequence.
An early study of bacterial vaginosis (BV) involved comparisons of the pH of vaginal fluids of women known to be suffering from BV with those known to be free of the disease. Gardner, H. L., et al., Am. J. Obstet. Gynecol. 69:962 (1955). All of the BV positive women in the study were determined to have a vaginal fluid pH greater than 4.5, and 91% of these women had a vaginal fluid pH greater than 5.0. Of the normal (disease-free) women in the test, 92% were found to have vaginal pH between 4.0 and 4.7. The conclusion drawn from the study was that a vaginal pH equal to or greater than 5.0 in conjunction with other clinical criteria was indicative of the presence of BV.
Subsequent studies culminating by Amsel, R., et al., Am. J. Med. 74:14-22 (1983), resulted in a reduction of the pH threshold for BV to 4.5, and established the remaining criteria as vaginal fluid homogeneity, the whiff test (treatment with alkali followed by an olfactory test to detect for an amine odor), and the presence of clue cells. These are commonly referred to as the Amsel clinical criteria for BV. The conclusion was based on a study group of 397 women in which 81% of BV positive women were found to have a pH greater than 4.5 while only 23% of the normal women were found to have a vaginal fluid pH greater than 4.5.
Studies subsequent to the report by Amsel et al. have now adjusted the pH threshold to 4.7. One of these is the study of Holst, E., J. Clin. Microbiol. 28:2035-2039 (1990), in which 100% of the women diagnosed as BV positive by the Amsel criteria were reported to have vaginal fluid pH greater than 4.7. Another is the study by Eschenbach, D. A., Am. J. Obstet. Gynecol. 158(4):819-828 (1988), in which all 257 women in the study group who had at least 20% clue cells were shown to have a vaginal fluid pH greater than or equal to 4.7, leading to the conclusion that a threshold value of 4.7 correlated best with the other clinical evidence of BV. Krohn, M. A., et al., J. Clin. Microbiol. 27(6):1266-1271 (1989), also verified the correlation between the vaginal fluid pH threshold of 4.7 and the presence of clue cells, and Holmes, K. K., and coworkers further confirmed the pH 4.7 threshold as an indicator of BVxe2x80x94Holmes, K. K., et al., eds., Sexually Transmitted Diseases, McGraw-Hill, New York (1990), Chapter 46:527-545 (Holmes, K. K., et al.), and Chapter 47:547-559 (Hillier, S. L., et al.).
The whiff test, which is one of the Amsel criteria, originated in a study by Pheifer, et al., N. Engl. J. Med. 298:1429-1434 (1978), that reported the presence of a characteristic fishy amine odor upon the addition of 10% KOH to a vaginal fluid specimen from a woman with BV. The odor is caused by the alkaline volatilization of amine salts found in the vaginal fluid of women with BV. Unfortunately, the test is highly subjective, it exposes the health care worker to potential biological hazards, and it is disagreeable and vulnerable to error, since it is performed on a microscope slide which, due to the transient nature of the amine odor, must be placed directly under the nose and sniffed immediately after the addition of the KOH.
Alternatives to the whiff test are analytical procedures such as high voltage electrophoresis (Chen, K. C. S., et al., J. Clin. Invest. 63:828-835 (1979)), thin-layer chromatography (Chen, K. C. S., et al., J. Infect. Dis. 145:337-345 (1982), and Sanderson, B. E., et al., Br. J. Vener. Dis. 59:302-305 (1983)), gas chromatography (Gravett, M. G., et al. Obstet. Gynecol. 67:229-237 (1986), and Dravenieks, A., et al., J. Pharma. Sc. 59:495-501 (1970)), and high-performance liquid chromatography (Cook, R. L., et al., J. Clin. Microbiol. 30:870-877 (1992)). These procedures, although more accurate and reliable than the whiff test, are expensive, time-consuming, and not suitable for on-site testing in a physician""s office or clinic.
Clue cells, which constitute a further Amsel criterion, are independently correlated with BV, and in the hands of a skilled microscopist are a very sensitive and specific indication of this infection. Clue cells are squamous vaginal epithelial cells found in vaginal fluid when BV is present. The cells are covered with numerous bacteria, giving them a stippled or granular appearance, and their borders are obscured or fuzzy because of the adherence of numerous rods or cocci. According to standard clinical practice, a diagnosis of BV is established when at least 20% of the detectable epithelial cells are clue cells. Holmes, et al., Sexually Transmitted Diseases, 2d ed., McGraw-Hill, Inc., New York, 1990.
Distinguishing between true clue cells in which the adherent bacteria completely obscure the edges of the cells and cells with simply a few adherent bacteria requires training and experience. One source of error is similarity in appearance between clue cells and trichomonads, white blood cells and other vaginal fluid components, frequently resulting in an incorrect identification of these cells as clue cells, and therefore false positive test results. Another is that clue cells when present are frequently obscured by numerous vaginal fluid components causing the clinician to miss the clue cells completely or to quantify them at levels below their actual level. This can result in a false negative test result. Therefore, it would be highly desirable to have a distinct analyte that is accurately and conveniently monitored and whose presence is correlated with clue cells.
U.S. Pat. No. 5,217,444 to Schoenfeld teaches an absorbent pad, for use in absorbing secretions from a person""s body, which includes a pH indicator material indicating by a color change the acidity or alkalinity of a liquid coming into contact with it. The pH indicator material is wetted by the secretions absorbed by the pad, and thereby provides an indication of the health condition of the person""s body.
U.S. Pat. No. 5,853,669 to Wolfbeis teaches a hydrophilic accommodating layer disposed on a hydrophobic mechanically stable support element, which layer contains an indicator dye in an immobilized form for the purpose of visual or optical indication of the pH of a sample which can be used as the pH indicator in the pad of Schoenfeld and in other applications as well.
The prior art teaches devices which, upon contact with liquid bodily secretions, has the capacity to change color by virtue of a pH indicator contained in the device. To this end, see U.S. Pat. Nos. 5,217,444 which is further described above and 5,769,813. In many cases an aberrant pH is an indication of a pathological state, for example an infection by a pathogen. Although the aforesaid prior art device indicates that there is a need for a specific medical diagnosis, it does not provide such a diagnosis. It does, however, suggest that there is sufficient biological material contained in the absorbent material of a tampon or hygienic pad to be used for medical diagnostics. This is especially true if analytical methods such as PCR or ELISA, which have signal amplification as inherent properties, are employed to make a final diagnosis.
Use of vaginal secretions contained in an absorbent pad (tampon or hygienic pad) offers a number of advantages when compared to other methods of obtaining samples of the same secretion. For example, most patients are capable of inserting and removing such a pad without aide. This means that a sample can be obtained without a gynecological examination. In addition, a patient suspecting an infection could bring or send a pad containing a sample to her doctor, making a subsequent appointment to receive the results and a prescription for treatment, if so required. This reduces the number of necessary medical appointments, an advantage for both patient and doctor. In some situations, for example patients living in remote areas, it is conceivable that a pad containing a sample would be mailed to a medical center, with results and prescription being returned by phone or fax.
The prior art also teaches pads with devices for collecting blood (U.S. Pat. No. Re:29,061) and for testing for microorganisms (U.S. Pat. No. 3,934,575) contained therein.
The present invention represents an improvement on the aforesaid prior art devices because it facilitates automated and detailed diagnosis or diagnoses from a single pad.
Automated sampling devices are known in the prior art. U.S. Pat. No. 4,120,662, for example, teaches a device which can withdraw liquid samples from a series of reservoirs loaded into a rack via the use of robotics. U.S. Pat. No. 5,846,490 teaches a device which automatically supplies test strips to an analyzing device. U.S. Pat. No. 5,865,975 teaches a device which automatically performs electrophoretic analysis of DNA fragments. U.S. Pat. Nos. 4,994,751; 5,154,889 and 5,425,918 teach additional devices for automated fluid analysis, chemical analysis and immunohistochemical analysis. The above listed patents are incorporated herein by reference.
However, all of the devices disclosed in the prior art are structurally and functionally inadequate for automatically collecting and thereafter analyzing vaginal secretions from an absorbent pad such as a hygienic pad or tampon.
There is thus a widely recognized need for, and it would be highly advantageous to have, an automated device for diagnosis of vaginal or cervical pathologies via analysis of secretions found in an absorbent pad such as a hygienic pad or tampon.
According to one aspect of the present invention there is provided a device for automatic analysis of bodily secretions collected in an absorbent pad, the device comprising (a) a platform; (b) a first mechanism being supported by the platform for accepting, holding and advancing the absorbent pad along the platform; (c) a second mechanism being supported by the platform for identifying at least one location being suitable for the analysis; (d) a third mechanism being supported by the platform for exposing a portion of the absorbent pad; and (e) a fourth mechanism being supported by the platform for performing a biochemical analysis of the bodily secretions present in at least one of the locations.
According to further features in preferred embodiments of the invention described below, the device is further for subsequent disposal of the pad, the device further comprising a disposal chamber for accepting the absorbent pad following the biochemical analysis.
According to still further features in the described preferred embodiments the first mechanism for accepting, holding and advancing the absorbent pad includes a proximal rolls unit and a distal rolls unit, each of the proximal and distal rolls units includes a roll biased against the platform, so as by controllably rolling the rolls, the first mechanism functions so as to accept, hold and advance the absorbent pad along the platform.
According to still further features in the described preferred embodiments the third mechanism for exposing a portion of the absorbent pad includes a proximal cutting unit and a distal cutting unit, each of the proximal and distal cutting units includes a moveable cutting element contactable with the absorbent pad, so as to form cuts in the absorbent pad, to thereby assist in exposing the portion of the absorbent pad.
According to still further features in the described preferred embodiments the portion is a membrane disposed within layers of the pad, the proximal and distal cutting units are so designed so as to form the cuts such that most of the remaining portions of the absorbent pad are removable by the first mechanism.
According to still further features in the described preferred embodiments the device further comprising a bridge translatable along the platform, the bridge serves for carrying both the second mechanism for identifying the at least one location suitable for the analysis and the fourth mechanism for performing the biochemical analysis of the bodily secretions present in at least one of the locations.
According to still further features in the described preferred embodiments the second mechanism for identifying the at least one location suitable for the analysis includes an optical sensor for sensing a color developed on the absorbent pad at a location of collected secretion.
According to still further features in the described preferred embodiments the color develops in response to pH.
According to still further features in the described preferred embodiments the fourth mechanism for performing the biochemical analysis of the bodily secretions present in at least one of the locations includes (i) a cartridge engaged on the bridge, the cartridge includes an opening and a plurality of moveable reservoirs moveably positionable against the opening so as to discard a liquid reagent content thereof through the opening; (ii) a funnel leading liquids from the opening to a surface of the portion of the absorbent pad at one of the at least one locations; and (iii) a suction operated liquid collecting and retaining container contactable with an opposite surface of the portion of the absorbent pad at one of the at least one locations; the liquid reagent content of the plurality of reservoirs are selected such that ordered application and removal thereof onto the portion of the absorbent pad at one of the at least one locations results in a developed indication which relates to the biochemical analysis.
According to still further features in the described preferred embodiments the reservoirs include at least one reagent selected from the group consisting of a primary antibody, a secondary antibody, a blocking reagent, a color reagent and a wash reagent.
According to another aspect of the present invention there is provided a method of analysis of vaginal secretions collected in an absorbent pad, the method comprising the steps of (a) using an absorbent pad for collecting the vaginal secretions, the absorbent pad including an inner membrane for absorbing at least a portion of the secretion, the inner membrane being embedded among layers of the absorbent pad, and an external, viewable membrane including a color indicator for indicating a location of secretions absorbed by the absorbent pad according to at least one parameter being indicative of a pathological state; and (b) if the pathological state is indicated, biochemically analyzing the inner membrane at a location respective to the location of secretions absorbed by the absorbent pad for further characterizing the pathological state.
According to further features in preferred embodiments of the invention described below, the at least one parameter is a pH value of the vaginal secretions.
According to still further features in the described preferred embodiments the pathological state is bacterial vaginosis.
According to still further features in the described preferred embodiments the step of biochemically analyzing the inner membrane is effected by an immunoassay.
According to still further features in the described preferred embodiments the step of biochemically analyzing the inner membrane at the location respective to the location of secretions absorbed by the absorbent pad for further characterizing the pathological state is effected by a device for automatic analysis of bodily secretions collected in an absorbent pad which includes (a) a platform; (b) a first mechanism supported by the platform for accepting, holding and advancing the absorbent pad along the platform; (c) a second mechanism supported by the platform for identifying a location of the color indicator if the pathological state is indicated by the color indicator; (d) a third mechanism supported by the platform for exposing at least a portion of the inner membrane; and (e) a fourth mechanism being supported by the platform for performing the step of biochemically analyzing the inner membrane at the location respective to the location of secretions absorbed by the absorbent pad.
According to still further features in the described preferred embodiments the first mechanism for accepting, holding and advancing the absorbent pad includes a proximal rolls unit and a distal rolls unit, each of the proximal and distal rolls units includes a roll biased against the platform, so as by controllably rolling the rolls, the first mechanism functions so as to accept, hold and advance the absorbent pad along the platform.
According to still further features in the described preferred embodiments the third mechanism for exposing the portion of the inner membrane includes a proximal cutting unit and a distal cutting unit, each of the proximal and distal cutting units includes a moveable cutting element contactable with the absorbent pad, so as to form cuts in the absorbent pad, to thereby assist in exposing the inner membrane.
According to still further features in the described preferred embodiments the device further includes a bridge translatable along the platform, the bridge serves for carrying both the second mechanism and the fourth mechanism.
According to still further features in the described preferred embodiments the second mechanism includes an optical sensor for sensing a color developed by the color indicator on the external membrane.
According to still further features in the described preferred embodiments the fourth mechanism includes (i) a cartridge engaged on the bridge, the cartridge includes an opening and a plurality of moveable reservoirs moveably positionable against the opening so as to discard a liquid reagent content thereof through the opening; (ii) a funnel leading liquids from the opening to a surface of the inner membrane; and (iii) a suction operated liquid collecting and retaining container contactable with an opposite surface of the inner membrane; the liquid reagent content of the plurality of reservoirs are selected such that ordered application and removal thereof onto the inner membrane results in a developed indication which relates to the biochemical analysis.
According to still further. features in the described preferred embodiments the device further includes a fifth mechanism supported by the platform for monitoring immunoassay produced fluorescence.
According to still further features in the described preferred embodiments the second mechanism also serves for detection of an ELISA produced color spot.
The present invention successfully addresses the shortcomings of the presently known configurations by providing a device and method for analyzing bodily fluids of bodily secretions to diagnose a pathological state. In particular, the present invention successfully addresses the shortcomings of the presently known configurations by providing an integrated device and method for analyzing bodily fluids which are collected into an absorbent pad.